<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>CSS 盒子模型</title>
    <style>
        .border-demo {
            background-color: yellow;
            width: 300px;
            height: 200px;
            border-style: solid dashed dotted double;
            border-width: 10px;
            /* border-width:10px 0 20px 40px
            遵从上右下左，顺时针旋转的顺序 */
            border-color: blueviolet;
            /* 对单一边框修改：
            border-left:10px solid brown; 
            border-left-color:red*/
        }

        .demo {
            background-color: lightblue;
            display: inline-block;
            border: 5px solid red;
            padding: 50px;
            margin: 40px;
        }
    </style>
</head>

<body>
    <div class="demo">花亦山心之月</div>
    <div class="border-demo">这是一个边框示例</div>
</body>

</html>